The invention relates to a process for the preparation of phenylketones etherified in the 4-position by reaction of aromatic ethers which have a free 4-position with conventional acylating agents on medium-pored or wide-pored zeolites having a pore size of at least 5 .ANG..
Aromatic ketones containing ether groups, for example 4-methoxyacetophenone or 4-methoxypropiophenone, are of great interest in the fragrance industry or as intermediates for other syntheses. The conventional method for the preparation of aromatic ketones is the homogeneous Friedel-Crafts acylation of aromatic hydrocarbons with carboxylic acid derivatives; in this form, acylation is also carried out in industry. For this purpose, at least stoichiometric, in most cases, however, excess amounts of the catalyst are, as is known, required, such as Lewis acids (AlCl.sub.3, FeCl.sub.3, BF.sub.3, ZnCl.sub.2, TiCl.sub.4) or proton acids (polyphosphoric acid, HF). Reference is made, for example, to the monograph by G. A. Olah, "Friedel-Crafts and related reactions", Wiley-Interscience, New York, Vol. I-IV (1963-1964) or to DE-OS (German Published Specification) 3,519,009. The problematical nature of Friedel-Craft catalysis when carried out in industry, that is, high costs through increased corrosion and also significant expenditure in handling, removal and disposal of the ultimately consumed catalyst, is sufficiently known.
In the special case where aromatics containing ether groups are used, moreover cleavage of the ether or rearrangement into the ring of the hydrocarbon radical bound to the ether oxygen must be expected in addition.